CSF CSG PDF - Harmonic Drive LLC

Torsional StiffnessTorsional StiffnessTorsional stiffness is determined by applying a load to the output of the gear, with the input rotationally locked. The angular rotationis measured as the load is increased. The typical curve (shown in the figure 11) is non-linear. The stiffness is determined the slopeof this curve. For simplicity, the curve is approximated by 3 straight lines having stiffness of K 1 , K 2 , and K 3 . Stiffness K 1 applies foroutput torque of 0 to T 1 . Stiffness K 3 applies for output torque greater than T 2 . Stiffness K 2 applies for output torque between T 1and T 2 .Typical stiffness values are shown in tables 41, 42, 43.Figure 10 Figure 11Torsional AngleATorsional AngleK3HysteresisB–T 0 0+T0TorqueK2B'Ø2Ø10K1TorqueT1T2A'Ratio 1/30 Table 41Size 8 11 14 17 20 25 32T 1 Nm 0.29 0.80 2.0 3.9 7.0 14 29K 1 X10 4 Nm/rad 0.034 0.084 0.19 0.34 0.57 1.0 2.4X10Ø -4 rad 8.5 9.5 10.5 11.5 12.3 14 12.11arc min 3.0 3.3 3.6 4.0 4.1 4.7 4.3T 2 Nm 0.75 2.0 6.9 12 25 48 108K 2 X10 4 Nm/rad 0.044 0.13 0.24 0.44 0.71 1.3 3.0X10Ø -4 rad 19 19 31 30 38 40 382arc min 6.6 6.5 10.7 10.2 12.7 13.4 13.3K 3 X10 4 Nm/rad 0.054 0.16 0.34 0.67 1.1 2.1 4.9Torsional Stiffness for Ratio 1/50 Table 42Size 8 11 14 17 20 25 32 40 45 50 58 65 80 90 100T 1 Nm 0.29 0.80 2.0 3.9 7.0 14 29 54 76 108 168 235 430 618 843K 1 X10 4 Nm/rad 0.044 0.22 0.34 0.81 1.3 2.5 5.4 10 15 20 31 44 81 118 162Ø 1 X10 -4 rad 6.6 3.6 5.8 4.9 5.2 5.5 5.5 5.2 5.2 5.5 5.2 5.2 5.2 5.2 5.2arc-min 2.3 1.2 2.0 1.7 1.8 1.9 1.9 1.8 1.8 1.9 1.8 1.8 1.8 1.8 1.8T 2 Nm 0.75 2.0 6.9 12 25 48 108 196 275 382 598 843 1570 2260 3040K 2 X10 4 Nm/rad 0.067 0.30 0.47 1.1 1.8 3.4 7.8 14 20 28 44 61 115 162 222Ø 2 X10 -4 rad 13 8 16 12 15.4 15.7 15.7 15.4 15.1 15.4 15.1 15.1 15.1 15.4 15.1arc-min 4.7 2.6 5.6 4.2 5.3 5.4 5.4 5.3 5.2 5.3 5.2 5.2 5.2 5.3 5.2K 3 X10 4 Nm/rad 0.084 0.32 0.57 1.3 2.3 4.4 9.8 18 26 34 54 78 145 206 283Numbers are average value.Torsional Stiffness for Ratio 1/80 and up Table 43Size 8 11 14 17 20 25 32 40 45 50 58 65 80 90 100T 1 Nm 0.29 0.80 2.0 3.9 7.0 14 29 54 76 108 168 135 430 618 843K 1 X10 4 Nm/rad 0.091 0.27 0.47 1 1.6 3.1 6.7 13 18 25 40 54 100 145 200Ø 1 X10 -4 rad 3.2 3.0 4.1 3.9 4.4 4.4 4.4 4.1 4.1 4.4 4.1 4.4 4.4 4.4 4.4arc-min 1.1 1.0 1.4 1.3 1.5 1.5 1.5 1.4 1.4 1.5 1.4 1.5 1.5 1.5 1.5T 2 Nm 0.75 2.0 6,9 12 25 48 108 196 275 382 598 843 1570 2260 3040K 2 X10 4 Nm/rad 0.10 0.34 0.61 1.4 2.5 5.0 11 20 29 40 61 88 162 230 310Ø 2 X10 -4 rad 8 6 12 9.7 11.3 11.1 11.6 11.1 11.1 11.1 11.1 11.3 11.3 11.6 11.3arc-min 2.6 2.2 4.2 3.3 3.9 3.8 4.0 3.8 3.8 3.8 3.8 3.9 3.9 4.0 3.9K 3 X10 4 Nm/rad 0.12 0.44 0.71 1.6 2.9 5.7 12 23 33 44 71 98 185 263 370Numbers are average value.50